In the retail industry, the largest expenditures are typically the cost of the goods sold followed closely by the cost of labor expended. With particular regard to the retail grocery or supermarket industry, the impetus to reduce labor costs has focused on reducing or eliminating the amount of time required to handle and/or process the items or goods to be purchased by a customer. To this end, there have been a number of self-service checkout terminal concepts developed which attempt to substantially eliminate the need for a checkout clerk.
A self-service checkout terminal is a system which is operated by a customer without the aid of a checkout clerk. In such a system, the customer scans individual items for purchase across a scanner and then places the scanned item into a grocery bag, if desired. The customer then pays for his or her purchase either at the self-service checkout terminal if so equipped, or at a central payment area which is staffed by a store employee. Thus, a self-service checkout terminal permits a customer to select, itemize, and in some cases pay for his or her purchase without the assistance of the retailer's personnel.
A customer typically has little or no training in the operation of a self-service checkout terminal prior to his or her initial use of the checkout terminal. One concern that retailers have when evaluating a self-service checkout terminal is the level of supervision provided to inexperienced customers. Moreover, it is also known that some customers may have improper intentions when using a self-service checkout terminal. In traditional checkout systems, the clerk employed by the retailer to operate the checkout terminal provides a level of security against theft or other improprieties. However, in the case of a self-service checkout terminal, the terminal itself must provide the necessary security. Such security includes preventing a customer from either inadvertently or intentionally placing an item in a grocery bag without scanning the item, or scanning one item, but placing a second item of greater value in the bag. Thus, another concern when evaluating a self-service checkout terminal is the level of security provided against illicit use of the self-service checkout terminal by customers.
Therefore, self-service checkout terminals have heretofore been designed with security systems which monitor the use of the self-service checkout terminal. For example, weight scales have been incorporated into self-service checkout terminals to monitor the manner in which a customer handles or otherwise processes items during operation of the self-service checkout terminal. In particular, self-service checkout terminals have heretofore been designed with a weight scale positioned under a bagging area associated with the self-service checkout terminal. After a customer scans or otherwise enters an item into the self-service checkout terminal, a processing unit associated with the self-service checkout terminal retrieves a stored weight value associated with the item. More specifically, the processing unit retrieves the stored weight value of the item by using the product identification code (e.g. a Universal Product Code or UPC) associated with the item to select the corresponding stored weight value from a number of values contained in a pre-defined, master product database. What is meant herein by the term "master product database" is a central database which includes product information (e.g. description, price, and weight) associated with every item that is sold by the retailer. When the scanned item is placed into a grocery bag positioned on the weight scale, the weight scale determines a measured weight value of the item which may be used by the processing unit to compare to the stored weight value of the item. In particular, the processing unit compares the stored weight value of the item to the measured weight value of the item in order to determine if the item that was placed in the grocery bag is the same item that was entered by the customer.
For example, if the customer scans a can of soup with the scanner, the product identification code associated with the can of soup is used by the processing unit to determine the stored weight value associated with the soup. In particular, the processing unit communicates with a memory device associated with the self-service checkout terminal in order to retrieve the stored weight value corresponding to the can of soup (e.g. 103/4 ounces) from the master product database. When the customer places the can of soup into a grocery bag, the weight of the can of soup is determined by the weight scale. In particular, if the customer places the can of soup into the grocery bag, the weight scale measures a weight corresponding to the can of soup (e.g. 103/4 ounces) thereby allowing the processing unit to conclude that a proper transaction has occurred. However, if the customer places a pound of steak into the grocery bag, the weight scale will measure a weight corresponding to the steak (i.e. 16 ounces) thereby causing the processing unit to conclude that an item substitution has occurred.
Such security systems which utilize a weight scale in the manner described above have a number of drawbacks associated therewith. For example, the effectiveness of the above described security system is undesirably dependent on the accuracy of the data stored within the master product database. In particular, if a stored weight value associated with a given item is inaccurate, the self-service checkout terminal will erroneously conclude that an item substitution has occurred, even if the proper item is placed in the grocery bag. Hence, it is imperative that the data within the master product database be maintained accurately. Such maintenance is particularly laborious in the grocery industry where the weight of a given item may change a number of times during a given period of time. For example, the weight of a given item may change if the item is featured in a promotion (e.g. a bottle of detergent which is normally sold in a 48-ounce bottle is being sold in a 58-ounce bottle at the same price). Moreover, the weight of the item may change of the manufacturer thereof changes the item's packaging (e.g. the detergent manufacturer replaces a plastic bottle with a glass bottle of the same size). If such a change in the weight of the item occurs, the retailer must first update the master product database to reflect the promotional weight value of the item (e.g. 58 ounces in the case of the detergent), and then update the master product database a second time to return the weight value to its original value (e.g. 48 ounces in the case of the detergent) upon completion of the promotion. Given the number of different items which are sold in a typical grocery store, it should be appreciated that such maintenance of the master product database is quite labor intensive thereby undesirably increasing costs associated with the items sold in the grocery store.
What is needed therefore is a self-service checkout terminal which detects item substitutions during operation thereof. What is further needed is a self-service checkout terminal which detects item substitutions without use of a master product database.